Halt! Who goes there?
The first line of defense is perimeter control at the site location, to prevent unauthorized access to the facility. As mentioned earlier in this chapter, physical security should be implemented by using a layered defense approach. For example, before an intruder can get to the written recipe for your company’s secret barbeque sauce, she will need to climb or cut a fence, slip by a security guard, pick a door lock, circumvent a biometric access control reader that protects access to an internal room, and then break into the safe that holds the recipe. The idea is that if an attacker breaks through one control layer, there will be others in her way before she can obtain the company’s crown jewels.